Wildfires in the Amazon are polluting the air with greenhouse gases faster than surviving trees absorb them. Photo: Nelson Almeida
Humans are transforming the Amazon rainforest. In fact, scientists have found that the Amazon has become another maker of climate change. Climate change is a major change in the Earth's climate over a long period of time. It can occur naturally and can also affect human activities.
The Amazon River spans much of South America. It contains approximately 2.8 million square miles (7.2 million square kilometers) of jungle.
Typically, forests absorb large amounts of carbon dioxide (CO₂) gas. That's because plants need it for photosynthesis. It's a process that involves using sunlight to produce food from carbon dioxide and water. By absorbing carbon dioxide, forests exclude it from the atmosphere, which is the layer of gas that surrounds the Earth. This is important because carbon dioxide is a greenhouse gas, which means it absorbs heat in the atmosphere.
In recent decades, humans have emitted large amounts of greenhouse gases. This emissions pollution comes from burning fossil fuels such as coal and oil. These materials release greenhouse gases such as carbon dioxide into the atmosphere. Over time, this activity can lead to higher global temperatures. It will eventually lead to climate change. All of these human activities make the Amazon jungle more important than ever in absorbing carbon dioxide.
But now, for the first time, scientists from Brazil have discovered that the Amazon releases more carbon dioxide than absorbs. In July 2021, scientists published their findings in scientific journals.
In their study, the scientists looked at nearly 600 carbon dioxide measurements from four locations in the Brazilian Amazon region. They used small aircraft to collect these measurements from 2010 to 2018.
Using these measurements, scientists found that wildfires were to blame for much of the carbon dioxide released by the Amazon jungle. Many fires are caused by people clearing land for agriculture and industry.
When trees burn, they release carbon dioxide and other greenhouse gases into the atmosphere. More greenhouse gases lead to longer, hotter dry seasons in the Amazon.
In particular, the eastern part of the Amazon jungle has become hotter, drier and more prone to fires than elsewhere in the rainforest. Over the past 40 years, deforestation or tree felling in the region has been more severe in history. The result is increased greenhouse gas emissions from fires and fewer trees absorbing carbon dioxide.
In fact, scientists have found that fires emit about 1.6 billion tons (1.5 billion metric tons) of carbon dioxide into the atmosphere each year. At the same time, healthy trees absorb only about 5 billion tons per year.
"The first very bad news is that forest burning produces three times as much carbon dioxide as forests absorb," Luciana Gati said. She led the study. Gatti is a researcher at the National Institute for Space Research in Brazil. The second bad news, she explains, is that the Amazon is releasing more carbon dioxide in more deforested places.
Gatti's team also found something encouraging: While the eastern Amazon jungle has become a source of carbon release, the western Amazon has not yet. It is balanced, and healthy forests absorb the same amount of carbon dioxide as fires release.
If we can stop fires in the Amazon, Garty said, forests could even become carbon sinks. This place absorbs more carbon dioxide than it releases. Limiting deforestation, especially wildfires, is key to reversing this dangerous trend, she said.
#2021 Life Conference ##Greenhouse Gas##Amazon Jungle##Wildfire##碳中和 #